A typical in-vehicle navigation system includes a receiver which receives position determination data from satellites, a microprocessor, a display and a map database. Typically, the position determination data is received from global positioning system (GPS) satellites which are a part of the GPS satellite network. The position determination data is processed via an electronics package located within the receiver or by the microprocessor unit. Most prior art in-vehicle navigation systems are self contained and do not interface with any outside sources other than the fact that they receive GPS data.
Other prior art systems use a display screen which displays a whole route map and the names of the landmarks within the whole route map. These types of prior art system requires an extensive storage mechanism to store the geographical information, the landmark information, and the navigation data needed for generating an accurate map display. These systems require a display screen that is large enough to show an entire area map. The display must also be high resolution so as to adequately project a detailed map image. These display screens are expensive. In addition, these systems require extensive data storage which is expensive. Moreover, a powerful microprocessor is required for processing the extensive amounts of data and generating the complex displays. In addition, due to the complexity of the map data required to generate a full map display, and due to limitations imposed by data storage media and the cost of data storage media for storing large amounts of data, these systems typically only upload and/or store data on a small region at any particular time. This necessitates frequent uploads of data when a user travels out of the limited area of a particular database. As a result, these prior art systems are expensive and are difficult to maintain and operate.
Some prior art vehicle navigation systems use CD ROM disks for storing data. CD ROM disks are a relatively inexpensive means for storing data and they are easy to install. Thus, storing the required data on the various geographic regions and updating the data is less burdensome for each in-vehicle computing system. Since most of the geographic information and navigation information in the database is required for generating the display, the information stored in each CD ROM must be constantly available to the navigation system. Therefore, prior art systems which use CD ROM disks which contain map data require a dedicated CD ROM player for playing the CD ROM. The requirement of a dedicated CD ROM adds a significant expensive to the navigation system. This also increases the size of the system.
What is needed is an inexpensive and easy to use navigation system. In particular, a navigation system is required which is inexpensive and which provides a user with only that information which the user requires in order to navigate through a particular geographic region. In addition, a system which does not require the storage of an extensive map database is required. A system which does not require the display of a large graphic display is also required. In addition, a navigation system which reduces processing requirements such that a cost effective data processing device may be used is required. A navigation system which can use CD ROM disks is also required.